Door closer and check



June 17, 1969 j RUSSELL ET AL 3,449,789

noon CLOSER AND CHECK Filed on. 5, 1966 Sheet JZra: 1.

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44k Cl RUSSELL June 17, 1969 F. J. RUSSELL T AL DOOR CLOSER AND CHECK Sheet 5 of 6 Filed on. s, 1966 Ian swaps, .fiZQED 02' 3 85541.,

June 17, 1 969 1 RUSSELL ET AL 3,449,789

DOOR CLOSER AND CHECK Filed Oct. 3, 1966 Sheet 4 of e 457 j/vrswafis. 44! 442 M50 cl. fll/SSEZL,

Fee P65 6. S 0401455/ Sheet of 6 June 17, 1969 F. .1. RUSSELL ET DOOR CLOSER AND CHECK Filed om. s, 1966 Sheet 6 of 6 June 17, 1969 F. J. RUSSELL ET DOOR CLOSER AND CHECK Filed Oct. 5, 1966 9 E x w W m L E d r M A w p m E 0 M s A 1 fm w E w a f 0 p Q Q w k 7 47 mum W Q QM www r m mm Q L Sm wa N Wm Sm 1 mm ..rIEHHHHHHWHJJWJ I! g aw w l y 7 /vv J/A/ WWW I u w E m m 7 mm. @m kw mwww mm -T, .I s E @Il s p mg Qmw m w %m m9 mwm @w QM mm @g United States Patent U.S. Cl. 1655 23 Claims ABSTRACT OF THE DISCLOSURE A door closer and check mechanism for a swinging door which is mountable within the floor below the door and serves both to pivotally support the door and variably control the speed and force with which the door closes. It includes adjustment of the static angular position of the door and incorporates combined height adjustmen't and levelling means for the mechanism prior to its permanent embedment in the floor. High and low speed discharge passages for hydraulic fluid are provided in a check cylinder as well as means for adjusting spring tension for door rotation. The mechanism provides for vertical and lateral door adjustment, for check cylinder pressure relief, and for temperature compensation within the hydraulic cushion.

The invention finds its principal application to door check mechanisms for single acting doors which are adapted to swing in one direction only from a closed position, although certain features of this invention are adaptable to doors which swing in both directions from a closed position.

An object of this invention is to provide a combination door check and pivotal support mechanism which incorporates improved means for adjusting the vertical, edge-to-edge and rotational angular position of the door relative to a door opening or an adjacent companion door.

Another object of this invention is to provide a door check mechanism which incorporates improved levelling means for the apparatus assembly prior to its permanent attachment or embedment in the floor.

Another object of this invention is to provide an improved door check assembly which permits submergence of substantially the whole moving mechanism, including the hydraulic cylinder components, in a body of hydraulic fluid which serves to reduce friction and wear and to keep the hydraulic cylinder components properly filled.

Still another object of this invention is to provide a door check assembly in which provision is made to accommodate the change in volume of the hydraulic fluid therein resulting from changes in temperature.

A still further object of this invention is to provide a door check assembly in which means is included for regulating the cushioning and checking action such as to compensate for changes in viscosity of the hydraulic fluid resulting from changes in temperature.

Still another object of this invention is to provide a door check device having a torque versus rotational angle characteristic such that the closing torque varies from a negative value close to its wide open position, increases abruptly to a positive value, as the opening angle decreases slightly from the wide open position, such positive value being maintained at a substantially constant value throughout the balance of the angular closing movement until it reaches an angle close to the fully closed position at which the closing torque substantially further increases, thereby insuring the completion of the closing of the door against an opposing force such as that applied by a latch or the like mechanism, and in case of a freely swinging door insuring its maintenance in a fully closed position against wind pressure or the like forces otherwise tending to open or hold it open slightly.

Another object of this invention is to furnish a door check device incorporating an automatic hold open feature actuatable for maintaining the door to which it is attached in its fully opened position.

A still further object of this invention is to provide an improved hydraulic check device which automatically controls the closing speed of the door in a manner which compensates for the varying closing torque between wide open and closed positions such as to maintain a substantially constant rate of closing movement.

A still further object of this invention is to provide safety means to protect the hydraulic check system against excessive pressures resulting from excessively rapid and forceful swinging of the door to which the device is attached.

Another object of this invention is to provide a door check mechanism which incorporates means in direct contact with the hydraulic fluid flow stream for continuously removing therefrom ferromagnetic metallic particles and the like contaminating materials, thereby protecting the operating characteristics and increasing the durability of the apparatus.

Still another object of this invention is to provide a door check mechanism having improved means for facilitating the adjustment of its several operating characteristics, including adjustment of the door hold open force, the checking and cushioning forces tending to oppose opening and closing movements, and that motivating the closing movement of the door to which the device is attached.

These and other objects, advantages and features of novelty will be evident hereinafter.

In the drawings which illustrate a presently preferred embodiment and mode of operation of the invention, and in which the same or similar reference characters designate the same or similar parts throughout the several views:

FIGURE 1 is a partially fragmentary, perspective view illustrating a typical installation of the door control mechanism of the invention in connection with a pair of adjacent, edge-to-edge mounted doors;

FIGURE 2 is an enlarged, fragmentary, partially schematic plan sectional view as taken approximately on line 22 of the left-hand one of the two doors and a portion of the door framing illustrating in FIGURE 1, showing the angular path and illustrating the action of the swinging movement of the door.

FIGURE 3 is a composite, vertical, longitudinal sectional view of the general assembly of the apparatus of the invention with portions thereof shown in elevation, as approximately taken on lines 33 of FIGURES 1 and 4, the vertical plane of the section being broken as indicated by line 3a3a, of FIGURE 6;

FIGURE 4 is a plan view of the assembly of the apparatus a-s taken from line 44 of FIGURE 3 with portions in section and portions removed to expose interior parts to view;

FIGURE 5 is a fragmentary, longitudinal sectional view of a door torque arm portion of the apparatus as viewed on line 55 of FIGURE 3;

FIGURE 6 is a fragmentary, vertical sectional, detailed view of the adjustable pivot portion of the apparatus as viewed on line 66 of FIGURE 3;

FIGURE 7 is an enlarged, detailed, perspective view of one of the apparatus elements shown in FIGURE 6;

FIGURE 8 is an enlarged, fragmentary, plan view of a portion of the cam mechanism of the apparatus as it would be viewed approximately from line 8-8 of FIG 3 URE 3, showing the cams in 31 position corresponding to the fully closed position of the door;

FIGURE 9 is a fragmentary, plan view of the same apparatus shown in FIGURE 8, showing its position corresponding to a partially open position of the door;

FIGURE 10 is a fragmentary, plan view of the same apparatus shown in FIGURES 8 and 9, showing the cam mechanism in a position corresponding to a fully open position of the door;

FIGURE 11 is a fragmentary, detailed, vertical sec tional view, with portions thereof in elevation, taken on line 1111 of FIGURE 9;

FIGURE 12 is a fragmentary, vertical sectional, detailed view of a portion of the apparatus taken on line 1212 of FIGURE 10;

FIGURE 13 is a slightly enlarged, partially fragmentary, vertical, longitudinal sectional view of a portion of the apparatus shown in FIGURE 3, showing the movable elements thereof in a position corresponding to an open position of the door;

FIGURE 14 is a vertical, longitudinal sectional view of the same portion of the apparatus shown in FIGURE 13, showing the movable elements thereof in a position corresponding to a fully closed position of the door;

FIGURE 15 is an enlarged, fragmentary, detailed, vertical sectional view taken on line 1515 of FIGURE 13;

FIGURE 16 is an enlarged, fragmentary, longitudinal sectional view taken on line 16-16 of FIGURE 13;

FIGURE 17 is an enlarged, elevational, perspective view of an element of the apparatus of FIGURE 13;

FIGURE 18 is an enlarged, fragmentary, cross-sectional view taken on line 1818 of FIGURE 14;

FIGURE 19 is an enlarged, perspective, detailed view of an element of the apparatus shown in FIGURES l3 and 14; and

FIGURE 20 is a cross-sectional view taken on line 20-20 of FIGURE 13.

A ppara'tus Referring first primarily to FIGURE 1 in which a typical installation environment of the apparatus of the invention is partially schematically illustrated, 10 and 12 are conventional left-hand and right-hand, 180 swinging door panels, shown in their fully closed, edge-to-edge positions within a door opening partially shown at 17, and which are pivotally mounted for controlled swinging movement about vertical axes upon a pair of door control suspension assemblies shown generally at 14 and 16, constructed in accordance with the present invention. The door control assemblies 14 and 16 are suitably supported and submerged within a floor slab or door sill body 18. It will be noted that the door control assemblies 14 and 16 are, or may be, of opposite-hand construction adapting them to installation in connection with oppositely swinging doors as shown in FIGURE 1. However, for convenience of illustration and description, only the one-hand construction of the door control assembly shown generally at 14, namely that for left-hand swinging control, is hereinafter described in detail since only reversal of some of the components thereof determines whether such control unit shall be adapted to right-hand or left-hand operation. The pivots partially shown at 11 and 15 for the upper ends of the door panels 10 and 12 are not a part of the present invention and may be of any suitable conventional design.

Referring next primarily to FIGURES 3 and 4 in which a typical installation of the door control suspension assembly 14 is illustrated, 18 is a floor slab, the material and construction of which may vary from installation to installation, but which is herein illustrated, by way of example, as a conventional concrete slab in which a suitable depression 20 is originally provided or otherwise suitably formed, for containing the door control suspension assembly in a so-called submerged position, flush with or below the finished level of the floor.

The door control suspension assembly 14 is provided with an enclosing, initially open-topped, metal cement case 22. The cement case 22 is provided with three, 'integrally formed, external supporting lugs as best shown at 24, 26 and 28 in FIGURE 4, each such supporting lug being provided with a threaded, vertically adjustable levelling screw as shown at 30, 32 and 34, respectively. In the installation of the cement case 22 in the depression 20, the levelling screws 30, 32 and 34 serve as adjustable supporting legs by means of which the cement case 22 and the mechanism assembly contained therein are adjusted to a proper height and level position. Such level position is indicated by a circular bubble level device 36 which is permanently installed in a cylindrical recess 38 sunk into the top surface 40 of a mechanism case 42 which closely fits and is supported within the cement case 22 as hereinafter more fully described. After the cement case 22 is properly located and levelled in the depression 20, it is secured in place by filling the surrounding intermediate space with a suitable grouting material as shown at 44.

The mechanism case 42 takes the form of a one-piece, elongated, hollow metal casting having an elongated, relatively narrow, generally rectangular, closed-topped cylinder block portion shown generally at 46, and a relatively wider, generally cylindrical, initially open-topped cam housing portion shown generally at 48. The interior of the cylinder block portion 46 and cam housing portion 48 are separated by a crosswise-extending web or partition 50. The cylinder block portion 46 and the cam housing portion 48 are provided with suitable fluid intercommunication around or through the partition or web 50 by an interconnecting fluid duct 52, whereby the body of hydraulic fluid normally maintained in the mechanism case 42 can flow between the cam housing portion 48 and the cylinder block portion 46 as required in the operation of the apparatus as hereinafter described.

The top of the beforementioned cam housing portion shown generally at 48 is normally closed by means of a rectangular, removable cover plate 54 which is bolted to the top of the cam housing portion 48, with a gasket 62 therebetween, by means of a plurality of machine screws which pass through the cover plate 54 and into threaded sockets in the upper edge of the cam housing portion 48, as indicated at 56 in FIGURE 4. The proper positioning of the cover plate 54 upon the top of the cam housing portion 48 for accurate alignment of the bearings carried thereby, is insured by means of a pair of indexing pins 58 and 59 which make close tolerance fits through coaxial indexing holes in the cover plate 54 and upper edge of the cam housing portion 48, as indicated at 60, 61 in, FIGURE 3.

The mechanism case 42 is suspended in the cement case 22 at six "suspension points. Two of the suspension points are located on opposite sides of an intermediate portion of the cylinder block portion 46 and consist of a pair of laterally extending, integrally formed ears 66 and 68 which rest upon and are secured to a corresponding pair of supporting ledges 70 and 72 formed in a pair of laterally oppositely positioned flares 74 and 76 integrally formed in the opposite sides of the cement case 22. The other four of the suspension points are located at the corners of the cam housing portion 48 and consist of sunken supporting ledges 78, 80, 82 and 84 formed in the four corners of the generally rectangular shaped, end portion 86 of the cement case 22, and upon which the corresponding corners of the rectangular cover plate 54 rest. The cover plate 54 is secured to the ledges 78 and 84 by means of a pair of cap screws 88 and 90- which extend through bolt holes in the corners of the cover plate 54 and into correspondingly positioned, threaded holes in the ledges 78 and 84. Indexing pins 92 and 94 insure the proper positioning of the cover plate 54 relative to the rectangular portion 86 of the cement case 22.

Fixedly attached to and depending from the central portion of the cover plate 54 is a cylindrical spindle-bearing housing 96 containing a needle bearing assembly 98. Also provided in the bottom of the cam housing portion 48, vertically coaxial with the upper spindle-bearing housing 96, is a lower spindle-bearing recess 102 (see FIG- URE 11) containing a lower needle bearing assembly 104. Also contained in an upper increased diameter portion '106 of the lower spindle needle bearing recess 102, is a roller thrust bearing assembly 108. Vertically rotatably supported by means of the beforementioned upper spindle-bearing assembly 98, lower spindle-bearing assembly 104 and thrust bearing assembly 108 is a door spindle shaft 110. The spindle shaft 110 from the lower end to the upper end thereof is formed with a lower spindlebearing race surface 112, a flatted cam drive section 114, an upper needle bearing race surface 116, an O-ring groove 118, an externally threaded section 120, and a fiatted, upper end terminal or coupling portion 122. A downwardly facing, annular thrust shoulder 124 is formed at the lower end of the flatted section 114 which rests upon the upper annular race 126 of the beforementioned rthr-ust bearing assembly 108. An O-ring 128 contained in the beforement'ioned O-ring groove 118, serves as a rotatable, fluid-tight seal between the spindle shaft 110 and the adjacent upper bore portion 129 of the upper spindlebearing housing 96.

Provided at the upper end of the spindle shaft 110 is a quickly detachable, door height adjustable, door seating and coupling assembly, shown generally at 130. That portion of the door seating and coupling assembly 130 which is carried on the upper end of the spindle shaft 110 comprises an annular, vertical adjustment nut 132 screwed onto the beforementioned externally threaded section 120, and a split coupling sleeve 134 surrounding and grippingly engaging the flatted upper end portion 122 of the spindle shaft 110 and resting on the upper annular end surface of the annular adjustment nut 132. As best shown in FIGURE 7, the split coupling sleeve is preferably formed of two identical, diametrically opposite-1y confronting halves, 136 and 138, although it may be formed of one or more pieces with one or more suitably located splits to provide diametral expansion or contraction thereof. The enclosed interior pass-age formed between the halves 136 and 138 is shaped with inner flat surfaces to grippingly fit the exterior, upper flatted end portion 122 of the spindle shaft 110, and the outer surface presented by the halves 136 and 138 has the form of a cylindrical section, with diametrically opposite sides having upwardly diverging, plane, wedge surfaces 140 and 142. Each of the opposite halves 136 and 138 of the coupling sleeve 134 terminates at its lower end in an integrally formed, semi-circular collar portion as shown at 144 and 146, which together form a split, annular collar, the lower surface of which seats upon the upper surface of the annular adjustment nut 132.

That portion of the door seating and coupling assembly 130 which is carried on the lower edge of the door includes a torque arm 150 having a tapered socket passage 152 formed through an intermediate, laterally offset hub portion 153 thereof. (See FIGURES 5 and 6.) The laterally olfset hub portion 153 of the torque arm 150 extends outwardly through a slot 151 provided through one of the walls 188 of the lower edge portion of the door 10. The socket passage 152 is formed with a pair of inner, diametrically opposite, upwardly diverging flat surfaces 154 and 156, generally conforming to the shapes of the before-described exterior wedge surfaces 140 and 142 of the upwardly tapered portion of the split coupling sleeve 134, such that the inner diverging fiat surfaces 154 and 156 of the socket passage 152 make wedging seating engagement with and support the weight of the door through the outer flat wedge surfaces 140 and 142, respectively, of the split coupling sleeve 134 which weight is transferred therefrom through the coupling sleeve 134 6 and the collar portions 144 and 146 thereof to the adjustment nut 132.

If desired the arrangement of the several beforedescribed components of the door seating and coupling assembly including the spindle coupling section 122 and torque arm socket 152 may be inverted while maintaining the same quickly detachable and vertical door adjustment features thereof.

The upper surface of the torque arm 150, adjacent the beforementioned, laterally offset hub portion 153 containing the tapered socket passage 152, is slidingly engaged by the lower surface of a door edge attachment plate 158 which is secured by a plurality of machine screws, as shown at 160 and 162, to a bottom cross member 164 adjacent the lower end edge of the door 10.

The torque arm 150 is pivotally and longitudinally adjustably retained on the lower surface of the door edge attachment plate 158 by means of a cylindrical boss 168 which is fixed to and extends downwardly from the door edge attachment plate 158 into a longitudinally elongated slot 170 formed in the torque arm 150 adjacent its lefthand end, as viewed in FIGURES 3 and 5. The boss 168 is provided with a crosswise extending, internally threaded passage containing a threaded adjustment screw 174. The length of the adjustment screw 174 is such that the opposite ends thereof are in rotatable abutment with the longitudinally opposite ends of the slot 170. The lefthand end of the adjustment screw 174 is provided with a hexagonal recess 176 for receiving the end of a hexagonal adjusting wrench. Access to the recessed end of the adjustment screw 174 is provided through a coaxial opening 178 formed in the left-hand end of the torque arm 150 and which extends into the slot 170. Rotational adjustment of the adjustment screw 174 serves to move the arm longitudinally relative to the boss 168 and thus pro vides an edgewise positioning adjustment of the door 10, carried thereby, relative to the fixedly positioned spindle shaft 110. The slot 151 is made sufiiciently long to provide for such adjustments.

The opposite or right-hand end of the torque arm 150 as viewed in FIGURES 3 and 5, is provided with an angular adjustment mechanism, shown generally at 180 in FIGURES 3 and 5, by means of which the rotational, angular position of the torque arm 150 about the center of the boss 168 may be varied, and thereby, in effect, the horizontal angular position of the vertical plane of the door 10 may be adjusted relative to the spindle shaft 110.

The angular adjustment mechanism 180 comprises a pair of oppositely directed, crosswise-extending, machine screws 182 and 183 which extend from a pair of longitudinally slidable washers 184 and 185 through longitudinally elongated holes 186 and 187, respectively, in the opposite walls 188 and 189 of the lower edge portion of the door 10 and into threaded engagement with crosswise-extending threaded holes 191, 192, respectively, formed through the torque arm 150 adjacent its righthand end as viewed in FIGURES 3 and 5. By suitable rotational manipulation of the adjusting machine screws 182 and 183, the right-hand end of the torque arm 150 may be moved horizontally crosswise of the width of the door 10, with resultant change in the horizontal angular position of the longitudinal axis of the torque arm 150 relative to the plane of the door 10. The elongated holes 186 and 187 in the walls 188 and 189' of the door 10 permit such horizontal or longitudinal movement of the torque arm 150 as may result from longitudinal adjustment of the position of the torque arm 150 relative to the boss 168 by means of the adjustment screw 174, as beforedescribed.

The right-hand end of the torque arm 150 is provided with two pairs of threaded holes 191, 192, as best shown in FIGURE 3, for receiving the beforedescribed crosswise adjustment screws 182 and 183 alternatively to "7 accommodate different configurations of the bottom edges of doors to which the apparatus may be applied.

By rotational adjustment of the annular adjustment nut 132, the height of the split coupling sleeve 134 which rests upon it may be adjusted relative to the spindle shaft 110, and thus, in turn, the torque arm 150, door edge attachment plate 158, and the door 10 to which it is attached may be adjusted vertically relative to the spindle shaft 110 and thus relative to the floor level. By reason of the wedging action of the split coupling sleeve 134 when subjected to the weight of the door, a firm wedging grip, free from lost motion, is maintained between the socket passage 152 of the torque arm 150 and the flatted upper end portion 122 of the spindle shaft 110 under all such adjusted conditions.

Referring next primarily to the cylinder block portion 46 of the mechanism case 42 of the apparatus assembly, as best shown in FIGURES 3, 13 and 14, such cylinder block portion 46 is formed with a longitudinal cavity extending from the aforementioned intermediate partition 50, to the right-hand end thereof, as viewed in the figures, such longitudinal cavity having a check cylinder bore portion 193 at the right-hand end portion therein and an intermediate plunger housing portion 194 of slightly increased inside dimensions relative to the check cylinder bore portion 193. The cylinder bore portion 193 is closed at its right-hand end by means of a cylinder head, shown generally at 195. The cylinder head 195 is formed with a cylindrical projection 196 which extends coaxially into the end of the cylinder bore 193 and which is provided with an annular O-ring seal 197 which provides a fluidtype seal between the cylinder head 195 and the cylinder bore 193. The cylinder head 195 is held in place on the right-hand end of the cylinder block portion 46 by means of four countersunk-head, machine screws which pass through holes in the cylinder head 195 and into threaded sockets in the end of the cylinder block portion 46, such machine screws being shown in cross-section at 198, 200, 202 and 204 in FIGURE 20, and two of them being shown in broken lines at 198 and 200 in FIGURES 13 and 14.

Axially, slidably contained within the check cylinder bore 193 is a check piston 206 having a piston head 208 and cylindrical skirt 210. The head 208 of the check piston 206 is provided with an encircling, annular O-ring seal 212 which makes an axially slidable, fluid-tight seal between the check piston 206 and the check cylinder bore 193, and the skirt portion 210 is provided with an annular wear ring 214 contained in an annular groove 215. The

wear ring 214 may be made of suitable material, such as, for example, Teflon, such ring serving to reduce the frictional sliding force between and wear of the surfaces of the check piston 206 and check cylinder bore 193.

Formed integrally, and positioned coaxially of the inner, left-hand face of the piston head 208, within the skirt portion 210 of the check piston 206, is a hollow cylindrical connector collar 216 into which is threadedly connected at 218, a piston rod assembly, shown generally at 220. The piston rod assembly 220 comprises a relatively large-diametered piston rod 222 and a relatively smaller diametered piston plunger 224 coaxially coupled together end-to-end by coupling means 226. The coupling means 226 includes a hollow, cylindrical sleeve 228 integrally formed on the right-hand end of the piston plunger 224 and into which extends a reduced diametered, cylindrical connector portion 230, integrally formed on the left-hand end of the piston rod 222, such connector sleeve 228 and connector projection 230 being secured together by means of a crosswise extending connector pin 232.

The left-hand end portion of the piston plunger 224 is axially slidably supported in a plunger guide bore 234 which extends coaxially through a plunger guide and cushioning cylinder assembly shown generally at 236, which, in turn, is rotatably supported in a cylindrical bore or opening 238 coaxially formed in the hereinbeforementioned partition or web 50. The right-hand portion of the plunger guide and cushioning cylinder assembly 236 is formed with a coaxially extending cylindrical cushioning cylinder 239 which is externally threaded as shown at 240 and which is provided with an internal bore 242 which terminates at its left-hand end in an axially diverging, frusto-conical entrance portion 244. The bore 242 of the cushioning cylinder 238 and the before-mentioned frusto-conical entrance portion 244 thereof, in operation, cooperate with a hydraulic cushion piston 246 integrally formed on the intermediate portion of the before-mentioned piston plunger 224.

The hydraulic cushion piston 246 comprises an increased outside diametered portion 248 on an intermediate portion of the piston plunger 224, the left-hand end portion of which is formed with an axially diverging, frustoconical entrance end portion 250. The increased outside diameter portion 248 of the hydraulic cushion piston 246 is provided with an external, encircling O-ring seal 252. An O-ring seal 253 is also provided in the plunger guide bore 234 of the plunger guide and cushion cylinder assembly 236 adjacent the bottom end of the cushion cylinder bore 242, which provides an axially sliding fluid seal between the piston plunger 224 and plunger guide and cushion cylinder assembly 236. An annular wear ring 255 composed of a suitable low friction material such as Teflon is also provided in a radially inwardly facing groove formed in the plunger guide bore 234, for reducing the frictional sliding force between wear of the surface of the piston plunger 224 and plunger guide bore 234.

Extending coaxially inwardly from the right-hand coupling end of the piston plunger 224 is a blind-ended bore 256 in which is contained a cushion piston hydraulic fluid bypass and thermostatic control assembly shown generally at 258. The thermostatic control assembly 258 comprises an elongated, generally cylindrical, tubular insert body 260 having an outside diameter less than the inside diameter of the bore 256 except at an intermediate section where, as shown at 262, an interval of increased outside diameter is provided which fits within the beforementioned bore 256. An O-ring seal 264 is provided around the interval of increased outside diameter 262. The beforementioned tubular insert body 260 is provided with an axial passage 266 extending therethrough from end to end which is of uniform inside diameter except for a relatively short aperture 268 at the left-hand end thereof of relatively reduced inside diameter, the inner or right-hand end of which aperture 268 constitutes a needle valve seat as will be hereinafter more fully described. The right-hand end of the axial passage 266 is closed by means of a press-fitted end plug 27 0.

Coaxially contained and supported within the axial passage 266 within the tubular insert body 260 is an elongated, rod-shaped, thermostatic element 272. The thermostatic element 272 preferably is rectangular in cross section with its maximum, transverse, diagonal dimension only slightly less than the internal diameter of the axial passage 266, whereby the thermostatic element 272 is maintained coaxially centered therein. The lefthand end of the thermostatic element 272 is formed with a pointed needle valve end 274 which extends coaxially into the aperture 268 of the tubular insert 260 and together with the inner annular endge of the aperture 268 serves as a needle valve for varying the effective size of the annular flow passage thereby formed between the inside of the aperture 268 and the pointed needle valve end 274. The right-hand end of the thermostatic element 272 bears against the inner surface of the end plug 270. A pair of fluid bypass passages are formed through the wall of the piston plunger 224, one of such passages 276 being located axially on the right-hand side of the hydraulic cushion piston 246 and the other passage 278 being located axially on the left-hand side of the hydraulic cushion piston 246. A fluid bypass path is thereby normally provided around the hydraulic cushion piston 246 in either direction by way of fluid passage 278, the annular space 281 between the left-hand end portion of the reduced diametered portion of the tubular insert 260, in through the aperture 268, past the needle valve point 274, thence through the clearance space between the thermostatic element 272 and the axial passage 266 within the tubular insert 260, from there through a radial aperture 280 into the annular clearance space 282 between the outside of the right-hand portion of the tubular insert 260 and the inside of the bore 256 of the tubular insert 260, and thence out through the fluid passage 276.

In operation, upon axial movement of the piston rod assembly 220, in a left-hand direction, corresponding to an opening swinging movement of the door, the hydraulic cushion piston 246 moves between a position as shown in FIGURE 14 in which it is in a withdrawn position relative to the bore 242 of the hydraulic cushion cylinder 239, to a position as shown in FIGURE 13, in which it enters the bore 242 of the hydraulic cushion cylinder 239, and in which latter position the O-ring seal 252 makes axially sliding sealing engagement between the cushion piston 246 an dthe bore 242 of the hydraulic cushion cylinder 239. As the hydraulic cushion piston 246 moves into the hydraulic cushion cylinder bore 242, the hydraulic fluid entrapped therein is caused to flow by way of escape into the fluid passage 278 and thence out through the fluid passage 276 by way of the flow passage hereinbefore described. The resistance to such flow of hydraulic fluid and thus the force opposing the movement of the cushion piston 246 into the hydraulic cushion cylinder bore 242 is determined, for the most part, by the beforementioned size of the needle valve opening existing between the inner edge of the needle valve aperture 268 and the needle valve point 274.

The thermostatic element 272'is preferably composed of a material which has a high coefficient of expansion relative to the material of which the surrounding tubular insert 260 is composed, whereby, as the thermostatic element 272 and the tubular insert 260 are subjected to hydraulic fluid of increased temperature under which condition the viscosity of the hydraulic fluid is normally reduced, the thermostatic element 272 expands in length relative to its surrounding tubular insert 260, thereby moving the needle valve point 274 further into the aperture 268, thereby reducing the size of the annular flow passage therebetween with resultant increase in resistance to flow of the hydraulic fluid therethrough. Conversely, when the thermostatic element 272 and its surrounding tubular insert 260 is subjected to hydraulic fluid of reduced temperature, the thermostatic element 272 will contract in length relative to the surrounding tubular insert 260, thereby withdrawing the needle valve point 274 from the aperture 268, thereby increasing the size of the flow passage therebetween, and thereby reducing the resistance to flow of hydraulic fluid therethrough. The action of the hydraulic thermostatic control assembly is, therefore, such as to tend to maintain the cushioning effect of the action of the hydraulic cushion piston 246, relative to the hydraulic cushion cylinder 239, relatively constant under conditions of varying hydraulic fluid temperature, which temperature variation may be caused by variation in the ambient temperature of the surroundings and by the frequency and rapidity with which the door check apparatus is used, with resultant dissipation of heat therein.

Threaded onto the externally threaded portion 240 of the hydraulic cushion cylinder 239 is a generally annular shaped, spring compression or bias adjusting nut 254. The spring compression adjusting nut 254 is formed with an integral, radially extending key 284 which makes nonrotatable, but axially slidable, engagement within a key slot 286 formed longitudinally along the inner, upper surface of the intermediate plunger housing portion 194.

The plunger guide and cylinder assembly 236 are formed with a radially extending, flanged portion 288, thereby providing an axially facing, radially extending, annular shoulder 290 adapted rotatably and slidably to bear against the adjacent face of an annular thrust washer 292, which, in turn, is retained against an oppositely facing, annular shoulder 294 formed in an annular depression in the before-mentioned partition 50, coaxially surrounding the cylindrical bore 238 therein, in which the plunger guide and cushioning cylinder assembly 236 is rotatably supported.

The before-mentioned radially extending, annular flange 288 of the plunger guide and cushioning cylinder assembly 236 is provided with a plurality of circumferentially spaced-apart, radially outwardly facing, pin sockets as shown at 296. By means of a pin or suitable hook wrench, which may be inserted through an access opening 298 formed through the upper intermediate wall of the mechanism case 42 while cover plate 300, normally held in place by cap screws 301 and 303, is removed, (see FIGURES 3 and 4) the plunger guide and cushioning cylinder assembly 236 may be rotated relative to the rationally stationary spring compression adjusting nut 254, thereby adjusting the axial position of the spring compression adjusting nut 254 upon the externally threaded portion 240 of the cushioning cylinder 239. A relatively heavy helical power spring 302 extends under compression between the right-hand, annular face of the spring compression adjusting nut 254 and the left-hand annular face 304 of the head portion 208 of the check piston 206, and the effective length thereof may be adjusted by means of the spring compression adjusting nut 254 whereby the force tending to move the check piston 206 in either direction axially within the check cylinder bore 193 may be adjusted.

Formed within the right-hand end portion of the piston rod 222 is a blind-ended relief valve bore 306, the bottom end of which communicates with the annular space surrounding the piston rod 222, by way of a radial passage 308. An axial aperture 310 is formed through the center of the head 208 of the check piston 206, said aperture 310 having an outer entrance portion 312 of relatively reduced diameter, thereby forming an inwardly facing annular shoulder 314 against which the base of a helical check valve spring 316 bears. Coaxially contained within the right-hand end portion of the relief valve bore 306, and axially movable therein, is a relief valve body 318, having formed on the right-hand end thereof a frusto-conical valve head surface 320 (see FIGURE 19) normally making seating engagement with a correspondingly shaped relief valve seat surface 322 formed at the inner end of the before-mentioned axial aperture 310. A helical spring 324 acting under compression between the blind-ended bottom of the relief valve bore 306 and the left-hand end of the relief valve body 318, serves normally to bias the relief head surface 320 into a closed position against the relief valve seat surface 322.

The relief valve body 318 is provided with a coaxial bore 326 extending therethrough from end-to-end, and terminating at its right-hand end is an outwardly facing spherical check valve seat 328 upon which a check valve ball 330 is normally seated and biased toward such seated, closed position by the beforementioned helical check valve spring 316. The force characteristics of the helical relief valve spring 324 relative to that of the helical check valve spring 316 are such as normally to maintain the valve head surface 320 in closed position against the relief valve seat surface 322 in opposition to the force of the helical check valve spring 316 acting through the check valve ball 330.

As best shown in FIGURE 19, the major portion of the otherwise cylindrical exterior surface of the relief valve body 318 is formed with diametrically opposite flat surfaces as shown at 332, 334, 336 and 338, whereby the major diagonal or diametral dimension thereof is only 1 1 slightly less than the inside diameter of the relief valve bore 306, thereby coaxially, slidably supporting the relief valve body 318 within the relief valve bore 306, yet providing axial flow passages through the clearance spaces provided between the flat surfaces 332-338 and the inside cylindrical surface of the aforesaid relief valve bore 306. A permanently magnetized, metallic body 480 is placed within the helical relief valve spring 324 within the relief valve bore 306, the purpose of which is hereinafter described in connection with the operation of the apparatus.

Referring again to the check cylinder head 208, as best shown in FIGURES 13 and 14, an axially extending, slightly laterally offset, check control valve bore 340 extends from the inside face 342 of the body of the cylinder head 195 to an annular shoulder 344 formed at the juncture therewith of a coaxial, closed-bottomed, reduced-diametered bore portion 346.

Axially contained within the check control valve bore 340 is a check control valve assembly shown generally at 348. The check control valve assembly 348 comprises two concentric elements, such elements consisting of a generally tubular shaped, external, valve sleeve element 350 press-fitted to a fixed position within the check control valve bore 340, a pair of O-ring seals 341 and 343 being provided therebetween, and an internal, generally tubular, valve plunger element 352 axially slidable between limits within the bore of aforesaid external valve sleeve element 350. The bore of the external valve sleeve element 350 is formed at its left-hand end with an interval 354 of reduced inside diameter and at its righthand end with an interval 356 or relatively increased inside diameter, such intervals being joined by an intermediate, frusto-conical valve seat surface 358. The valve plunger element 352 is formed with an axially extending neck portion 360 of reduced outside diameter relative to an inner body portion 362 of increased outside diameter, such neck portion 360 and body portion 362 being joined by a frusto-conical valve surface 364 having a taper corresponding to that of, and adapted to seat upon, the frusto-conical valve seat surface 358, when in the closed position, as illustrated in FIGURE 13. The valve plunger element 352 is adapted to reciprocate within the external valve sleeve element 350, between the open position thereof illustrated in FIGURE 14 and the closed position thereof illustrated in FIGURE 13, and the internal valve plunger element 352 is biased toward the closed position by means of a helical spring 366 acting under compression between the bottom of the reduced diameter bore portion 346 and the base end of the body portion 362 of the internal valve plunger element 352. The internal valve plunger element 352 is provided with a pair of O-ring seals, as shown at 368 and 370, which makes sliding, sealing engagement with the bore of the external valve sleeve element 350.

The internal valve plunger element 352 is formed with an axial passage 372 extending from end-to-end thereof which provides fluid communication between the left-hand end of the neck portion 360 extending within the check cylinder bore 193, and the reduced diameter bore portion 346 in the cylinder head 195. An O-ring seal 374 is attached coaxially to the left-hand end face of the neck portion 360 of the internal valve plunger element 362, which serves as a valve element to close the inner end of the axial passage 372 upon its making abutting contact with the end surface of the piston head 208 of the check piston 206, as illustrated in FIGURE 14.

The upper portion of the cylinder block portion 46 is provided with a hydraulic fluid flow passage 376 which extends longitudinally between the cylinder head end and the intermediate plunger housing portion 194 thereof. The head end of the fluid flow passage 376 is connected through a pair of divergent ducts 378 and 380, as best shown in FIGURE 16, with an intermediate side portion of a pair of cylindrical, valve sockets 382 and 384, re-

12 spectively, formed into the upper portion of the cylinder head 195. The bottom end of valve socket 382 is connected by way of a duct 386 with the reduced diameter bore portion 346 of the check control valve bore 340, which, in turn, communicates with the axial passage 372 extending through the internal valve plunger element 352. The bottom end of valve socket 384 is connected by way of a duct 388 with an intermediate section of the check control valve bore 340 (see FIGURE 15). The intermediate portion of the external valve sleeve element 350 is formed with an encircling annular groove 390 wihch c mmunicates with the duct 388 and which, in turn, connects through a plurality of radial passages, as shown at 392 extending radially through the wall of the external valve sleeve element 350, with the bore portion 356 of relatively increased inside diameter at a point adjacent the frustoconical valve seat surface 358.

The cylindrical valve socket 382 contains a hollow, cylindrical, closing speed, regulating valve element as shown at 394, and the cylindrical valve socket 384 contains a similar, hollow, cylindrical latching speed regulating valve element 396. Each of the hollow cylindrical valve elements 394 and 396 are identically formed, as best shown in FIGURE 17, having a central, downwardly opening valve cavity 398. The wall of each of the cylindrical valve elements formed between the inside diameter of the valve cavity 398 and the outside cylindrical surface thereof, is penetrated by an inwardly diverging, V- shaped, circumferentially extending slot as shown at 402, the outer openings of which are positioned to be communicable with the ducts 378 or 380, as the case may be, to an extent depending upon the rotational position of each of the cylindrical valve elements 394 or 396 in its corresponding valve socket 382 or 384, respectively.

The upper end of each of the cylindrical valve elements 394 and 396 is provided with a cylindrical, reduced diametered, upward projection 404 forming an upwardly facing annular shoulder, as best shown at 406 in FIGURE 17. In the installation of the cylindrical valve elements 394 and 396, as shown in FIGURES 4, 13 and 14, they are held in place axially within their corresponding cylindrical valve cavities 382 and 384, in the cylinder head 196, by means of a cover plate 408 which is provided with a pair of matching holes 410 and 412, through which the projections 404 of the cylindrical valve elements 394, 396, respectively, extend. The cover plate 408 is removably fastened to the top of the cylinder head 195 by means of countersink machine screws 397. The upwardly extending cylindrical projection 404 of each of the cylindrical valve elements 394 and 396 is provided with a screw driver slot, as shown at 414 in FIGURE 17, whereby rotational adjustment of the closing speed and latching speed valves may be effected. Each of the cylindrical valve sockets 382 and 384 is provided with O-ring seals straddling the entrance points of ducts 378 and 380, as shown at 416 and 418, for maintaining rotatable sealing engagement with the exterior cylindrical surface of each of the cylindrical valve elements 394 and 396 above and below the communicating ducts 378 and 380, respectively.

Reference is again directed pirncipally to FIGURES 3, 4 and 8-10 and to the cam housing portion 48 of the mechanism case 42 and the cam and follower mechanism assembly shown generally at 420 therein. Fixed upon the flatted section 114 of the spindle shaft and extending in vertically separated horizontal planes, is a lower, actuating cam 424 and an upper, check cam 426. The actuating cam 424 is vertically straddled by a generally triangular shaped, horizontally extending cam follower yoke structure shown generally at 428, such yoke structure 428 comprising upper and lower, vertically spaced-apart, generally triangular shaped, yoke plates 430 and 432, such yoke structure 428 having an apex end portion as shown at 434 and laterally opposite, symmetrically positioned base corners as shown at 435 and 437. The apex end portion 434 of the cam follower yoke structure 428 is connected to the left-hand end of the piston plunger 224 by means of a cross pin 439, and the upper and lower yoke plates 430 and 432 of the cam follower yoke structure 428 are each provided with an elongated slot as shown at 436 in FIGURES 8, 9 and 10, through which the spindle shaft 110 extends and which permits guided, axial movement of the cam follower yoke structure 428 relative to the spindle shaft 110.

Rotatably carried on a pair of pins 438 and 441 which are attached to and extend vertically between the upper and lower yoke plates 430 and 432 of the cam follower yoke structure 428 adjacent the base corners 435 and 437 therof, as best shown in FIGURE 10, are a pair of cam follower rollers 440 and 442, respectively. In the arrangement of the apparatus shown in the drawings, and as best shown in FIGURES 4, 8, 9 and 10, the cam follower roller 440 is so positioned as to ride on the cam surface of the lower actuating cam 424.

The opposite cam follower roller 442 is idle and does not perform any service in the particular arrangement shown in the figures, however, since the cam follower rollers 440 and 442 are symmetrically located relative to the common longitudinal axis of the cam follower yoke structure 428 and piston rod assembly 220, the presence of cam follower roller 442 makes it possible to turn the lower actuating cam 424 and upper check cam 426 over on the spindle shaft 110, whereupon the cam follower roller 442 will make contact with the cam surface of the lower actuating cam 424, and the cam follower roller 440 will be idle, thereby converting the check mechanism from a left-hand swinging device as shown in the figures, to a right-hand swinging device.

Rotatably carried on a pin 444 extending vertically from the upper yoke plate 430 adjacent the beforementioned apex end portion 434 of the cam follower yoke structure 428 is a cam follower roller 446 which is so positioned as to make following contact with the cam surface of the upper check cam 426.

The shapes of the cam surfaces of the lower actuating cam 424 and upper actuating cam 426 are such that they remain in substantial following contact with the cam follower rollers 440 and 446, respectively, at all rotational positions thereof, except at the positions thereof corresponding to a fully opened door position as will be hereinafter explained, whereby very slight, if any, lost motion results btween the rotational motion of the door spindle shaft 110 and the axial movement of the cam follower yoke structure 42 8 and the piston rod assembly 220 connected thereto.

The active cam surface of the lower, actuating cam 424 over which the cam follower roller 440 relatively moves, for example, when the actuating cam 424 is rotated counter-clockwise through an angle A from the position shown in FIGURE 8 to that shown in FIGURE 9, is shaped with an initial, radially abrupt rise 448 which extends through an angle, as shown at A, of approximately 3 and which quickly changes as shown at 450 to a gradually, continuing radially rising, intermediate arcuate portion 452 which extends through an angle as indicated at B, for approximately 110 to a point 454 at which it abruptly changes to a final cam portion 456 which is substantially straight and having a slightly negative rise and which extends through an angle as indicated at C of approvimately Because the movement of the cam follower roller 440 is parallel with the longitudinal axis and direction of motion of the cam follower yoke structure 428 and piston rod assembly 220', instead of being radial relative to the center of rotation 457 of the actuating cam 424, the actual full range of rotation of the actuating cam 424 is 180 even though the rotation thereof relative to the cam follower roller 440 is somewhat less than 180, as is apparent in the drawings.

As a result of the foregoing, for the first approximately of rotation of the door from its closed position, as

indicated at A in FIGURES 2 and 9, the check cam 424 and follower roller 440 move from the position shown in FIGURE 8 to that shown in FIGURE 9, during which the follower roller 440 moves to and just over the abrupt rise portion of the check cam 424 to the point 450 thereon. For the next approximate of rotation of the check cam 424, the follower roller 440 moves relative thereto through angle B, as indicated in FIGURES 2 and 9, to point 454 on the check cam 424 and thence finally through an angle of approximately 10, as indicated at C'/2 in FIGURES 2, 9 and 10, to the fully opened position shown in FIGURE 10.

The active cam surface of the upper check cam 426 over which the cam follower roller 446 relatively moves, for example, when the check cam 426 is rotated counterclockwise from the position shown in FIGURE 8 to that shown in FIGURE 10, is shaped with a spiral, radially receding surface portion, as shown at 425, extending from the point of contact 458 therewith of the cam follower roller 446, as shown in FIGURE 8, through a rotational angle, as indicated at D, of approximately to a point 460, at which it abruptly changes to a final cam portion 462 having the form of an outwardly facing, arcuate depression 462 which extends through a rotational angle as indicated at E for approximately 40.

Attached to the check cam 426 and extending upwardly from the upper face thereof is a detent insert 464 (see FIGURE 12) having formed in its upper end a detent recess 466. The detent recess 466 is adapted to receive an adjustable, spring pressed detent ball 468 in releasable latching engagement therewith. The detent ball 468 is vertically movably retained in the bore 470 of a cylindrical detent body 472, the upper end of which is inserted into and fastened in a hole 474 formed through the cam housing cover plate 54 at a point to the left of the spindle shaft 110 and in a plane which is vertical to the longitudinal axis of the piston plunger 224 and the piston rod assembly 220, as best shown in FIGURES 3 and 12. The spring bias on the detent ball 468 is adjusted by means of a threaded plug 471 threaded into the top of the detent body, whereby the axial force exerted by a helical spring 475 between the plug 471 and the detent ball 468 may be varied.

Operation The operation of the apparatus of the invention is as follows: Assuming for convenience of description that the apparatus is initially at rest in a position corresponding to that of a fully closed door, as illustrated in solid lines in FIGURES 1 and 2, at which the apparatus will be in the position illustrated in FIGURES 3, 4, 8 and 14, upon pushing the door in a direction to cause it to swing from a closed position to an opened position in a counterclockwise direction, as indicated by arrow 474 in FIG- URE 2, the following action and movements of the parts of the apparatus occur. The rotational force applied to the door, acting through the spindle shaft 110, applies counter-clockwise rotation to the cams 424 and 426, with the result that the cam follower roller 440, bearing on the actuating cam 424, is forced to move axially; and such axial movement of the cam follower roller 440, acting through the cam follower yoke 428, moves the piston rod assembly 220 and check piston 206 in a left-hand direction in opposition to the force of the helical power spring 302, from the position shown in FIGUR ES 3, 8 and 14 corresponding to the beforementioned fully closed position of the door, to the position shown in FIGURES 10 and 13 corresponding to a fully opened position of the door.

Over approximately the initial 30 of the counterclockwise rotation of the actuating cam 424 from a position thereof corresponding to the fully closed position of the door, as shown in FIGURE 8, to a position thereof corresponding to a slightly opened position, as shown in FIGURE 9, which corresponds to the angle indicated at A in FIGURES 2 and 9, the cam follower roller 440 is forced to move along the abrupt rise portion 448 thereof and around the quick change point 450' thereof, resulting in the cam follower roller 440, cam follower yoke 428, piston rod assembly 220 and check piston 206 connected thereto, being initially forced to move axially more rapidly relative to such initial rotational angular movement (angle A) of the actuating cam 424 than for the next following opening rotational movement thereof. As the opening rotational movement continues through the angle indicated at B in FIGURES 2 and 8, the follower roller 440 next moves along the arcuate, uniform, radial rise portion 452 of the actuating cam 424, with a resultant reduced rate of axial movement of the cam follower roller 440, yoke 428, piston rod assembly 220 and check piston 206. As a result of the foregoing cam action, the force required to start the opening movement of the door and to open the door to an initial, slightly opened position, and, conversely, the force tending to complete opposite closing movement of the door as it approaches a nearly closed position is relatively great as compared to the force required to complete the balance of the opening movement of the door and that tending to return the door to a nearly closed position. As the rotational movement of the door nears the completely opened position, the cam follower roller 440 moves past the abrupt change point 454 and onto the straight, negative rise portion 456 of the actuating cam 424 to the position shown in FIGURE 10, as a result of which the actuating cam 424- is imparted a reversed rotational torque tending to continue to rotate the cam and the door through the angle indicated at C'/ 2 in FIGURES 2 and 9 to its fully opened position. Finally, at the fully opened position of the actuating cam 424 relative to the cam follower roller 440, shown in FIGURE 10, the detent recess 466 on the check cam 426 and detent ball 468 carried on the cover plate 54, as beforedescribed, engage one another and thereby releasably latch the mechanism in the fully opened position.

Throughout the resulting movement of the piston 206 in the check cylinder bore 193 from the position shown in FIGURES 3 and 14 to that shown in FIGURE 13 as beforedescribed, hydraulic fluid, the level of which is shown at 482, contained in the cylinder block portion 46 of the mechanism case 42 is drawn into the space of increasing volume within the check cylinder bore 193 between the check piston head 208 and the check cylinder head 195 by way of radial passage 308, relief valve bore 306 and thence through coaxial bore 326 extending through the relief valve body 318, past the check valve 328, 330, and finally through aperture 312. During such flow of hydraulic fluid, the relief valve body 318- is maintained in seated, closed position, with the frusto-conical valve head surface 320 seated upon the valve seat surface 322 by reason of both the differential pressure resulting from the flow of the hydraulic fluid therethrough and the closing bias of helical valve spring 324.

As the piston rod assembly 220 moves in a left-hand direction as beforedescribed, from the position shown in FIGURES 14 to that shown in FIGURE 13, the hydraulic cushion piston 246 approaches and finally enters the bore 242 of the hydraulic cushion cylinder 239, to the position shown in FIGURE 13. During the initial entrance of the frusto-conical entrance portion 250 of the hydraulic cushion piston 246 into the bore 242 of the hydraulic cushion cylinder 239, the hydraulic fluid entrapped therein is initially forced to escape largely through the decreasing annular clearance space between the approaching frustoconical surfaces 244 and 250, with the result that a checking force is exerted on the hydraulic cushion piston 246, which force may be initially light but of a gradually increasing magnitude as the hydraulic cushion piston 246 completes its entrance into the hydraulic cushion bore 242 as the door nears the end of its swinging motion toward a fully opened position. As the movement of the hydraulic cushion piston 246 continues into the hydraulic cushion cylinder bore 242, the O-ring seal 252 is finally brought into sealing engagement with the inside cylindrical surface of the hydraulic cushion cylinder bore 242, thereby entrapping the hydraulic fluid within the space in the cushion cylinder 239, with the result that during the remaining and final movement, the hydraulic fluid is forced to escape therefrom by way of passage 276, annual clearance space 281, aperture 268, past the pointed end 274 of the thermostatic element 272, and thence through axial passage 266 within the tubular insert 260, and from there through the radial aperture 280 into annular clearance space 282 and out the fluid passage 276, and to return into the body of hydraulic fluid in the mechanism case 42. Resistance to such latter portion of the scape of hydraulic fluid from the hydraulic cushion cylinder bore 242 will largely result from the resistance to flow of the hydraulic fluid through the relatively small annular clearance space between the inside diameter of the orifice 268 and the outside surface of the pointed end 274 of the thermostatic element 272.

The action of the thermostatic element 272 is such that, as the temperature of the hydraulic fluid increases with resultant reduction in its viscosity, the length of element 2'72 increases relative to its surrounding tubular insert 260, thereby moving the needle valve point 274 further into the needle valve seat interval 268 and thereby reducing the size of the annular flow passage therebetween, with resultant increase in resistance to flow of the hydraulic fluid therethrough. Conversely, as the temperature of the hydraulic fluid therethrough decreases with resultant increase in its viscosity, the thermostatic element 272 contracts in length relative to its surrounding tubular insert 260, thereby withdrawing the needle valve point 274 from the valve seat interval 268, thereby increasing the size of the annular flow passage therebetween and thereby reducing the resistance to flow of hydraulic fluid therethrough. The action of the hydraulic thermostatic control assembly is, therefore, to maintain the cushioning effect of the action of the hydraulic cushion piston 246 relative to the hydraulic cushion cylinder 242 relatively constant under conditions of varying hydraulic fluid temperature, which variations, as hereinbefore mentioned, may be caused by variations of the ambient temperature of its surroundings and also by the amount of heat dissipated into the hydraulic fluid, depending upon the frequency and rapidity of operation of the door check apparatus.

As beforedescribed, once the mechanism reaches the position corresponding to a fully opened door position, it is held in an open position by reason of the negative torque resulting from the force of the cam follower roller 440 against the negative rise portion 454 of the actuating earn 424, together with the latching action of the detent mechanism, and substantial initial force on the door in a closing direction is required to dislodge the mechanism from such position and release it for free return to the closed position, under the actuating force of helical power spring 302.

Assuming next that the door is dislodged from a fully open position and permitted to swing freely to a fully closed position under the force of the helical power spring 302 acting through the cam follower roller 440 on the actuating cam 424, as soon as the cam follower roller 440 passes over the abrupt change point 454 thereof from the negative rise portion 456 to the arcuate uniform radial rise portion 452, a closing torque is thereby applied to the spindle shaft 110. Under the force of the beforementioned helical power spring 302, the check piston 206 moves in a right-hand direction Within the check cylinder bore 193 from the position shown in FIG- URE 13 to that shown in FIGURE 14. As the check piston 206 thus moves, the hydraulic fluid entrapped in the space within the check cylinder bore 193 and between the check piston 208 and the cylinder head 195 is forced to escape therefrom initially by way of a first escape passage which comprises the axial passage 372 through the neck portion 360 of the valve plunger element 352, bore portion 346 of the cylinder head 195, lateral duct 386, valve cavity 398 of the cylindrical valve element 394, valve slot 402, duct 378, and axial fluid flow passage 376 leading to the hydraulic fluid body 482 within the housing bore portion 193 of the mechanism case 42. During such initial portion of the right-hand movement of the check piston 206 within the cylinder bore 193, as beforedescribed, the valve plunger element 352 is in its maximum left-hand position within the valve sleeve element 350, with the frusto-conical valve surface 364 thereof in closed engagement with the frusto-conical seat surface 358, as shown in FIGURE 13.

As the check piston 206 approaches the right-hand limit of its stroke in the check bore 193, the inner face of the cylinder head portion 208 moves into sealing contact with the O-ring seal 374 carried on the inner end face of the neck portion 360 of the internal valve plunger element 352, thereby closing the inner end of the axial passage 372 extending therethrough and thereby closing off the previously described first escape passage. As the check piston 206 continues to move in a right-hand direction in the check cylinder bore 193 toward the end of its stroke, the internal valve plunger element 352 is forced by the check piston 206 to move in a right-hand direction within the external valve sleeve element 350, from the position shown in FIGURE 13 to that shown in FIGURE 14, in opposition to the helical valve spring 366. During such movement of the valve plunger element 352, a second escape passage for flow of hydraulic fluid from the check cylinder is thereby opened, such second escape passage comprising annular space 476 between the reduced diameter bore portion 354 of the external valve element 350 and the surrounding neck portion 360 of the internal valve plunger element 352, past the O-ring seal 368, through the plurality of radial passages 392 formed through the external wall of the valve sleeve element 350, into annular groove 390, duct 388 (see FIGURE 15) in the cylinder head 195, cavity 398 of the cylindrical valve element 396 (see FIGURES 16 and 17), valve slot 402, duct 380, and thence through the beforementioned axial fluid flow passage 376 leading to the body of hydraulic fluid 482 within the housing bore portion 194 of the mechanism case 42.

By rotational adjustment of the cylindrical valve element 394 for the closing speed and 396 for the latching speed, to vary the respective areas of the tapered valve slots 402 in each which are exposed to communication with the adjacent entrances into their respective connecting ducts 378 and 380 (see FIGURE 16), the resistance to escape of hydraulic fluid through the beforementioned first and second escape passages may be adjusted to any desired or required values to regulate the closing speed and the final latching speed of the door. Normally, the valve elements 394 and 396 are adjusted such that the resistance to flow through the first escape passage is lower than that through the second escape passage, whereby the checking action increases asthe check piston 206 approaches the end of its travel toward the cylinder head 195 corresponding to a closing position of the door.

In event an external closing force is manually applied to the door, a correspondingly forceful rotational torque is applied through the spindle shaft 110 to the check cam 426, tending to rotate it in a clockwise direction, as viewed in FIGURES 8, 9 and 10, with the result that the cam surface 425 thereof is moved into forceful engagement with cam follower roller 446 and with the result that a longitudinal force is transferred therefrom to the piston rod assembly 220 and to the check piston 206, tending to move check piston 206 in a right-hand direction in the check cylinder bore 193 at a greater than normal rate. In event such closing force manually applied to the door is severe or in excess of a predetermined limit, such that the escape of hydraulic fluid from the space between the check cylinder 206 and the cylinder head 195 by way of either of the beforedescribed first or second escape passages would be insufficient to prevent the building up of excessive hydraulic fluid pressure in the check cylinder and the subjecting of the mechanism to excessive stresses, the relief valve body 318 will be subjected to sufficient differential fluid pressure to cause it to be moved in a left-hand direction within the relief valve bore 306 within the piston rod 22, in opposition to the helical spring 324, suflicient to unseat the frusto-conical valve head surface 320' thereof from the frusto-conical valve seat surface 322, thereby permitting escape of hydraulic fluid around the relief valve body 318 and out through the radial passage 308 and into the body of hydraulic fluid within the housing bore portion 193 of the mechanism case 42, thereby relieving the pressure within the check cylinder and limiting the maximum stresses to which the apparatus components can be subjected.

It will be noted that, in normal operation, the reciprocation of the check piston 206 in the check cylinder bore 193 results in circulation of hydraulic fluid from and return to the body of hydraulic fluid 482 within the housing portion of the mechanism case 42 by way of the herein beforedescribed fluid flow passages, such path of circulation being -by way of the radial passage 308, relief valve bore 306, and thence through coaxial bore 326 extending through the relief valve body 318 past the check valve 328, 330, and through aperture 312 into the space in the check cylinder bore 193 between the check piston 206 and the check cylinder head 195, and thence, by way of the herein beforedescribed first or second escape passages in the check cylinder head 195, and a return through the axial fluid flow return passage 376 leading back to the beforementioned hydraulic fluid body 482 within the housing bore portion 193 of the mechanism case 42. As a result of this circulation of hydraulic fluid, it is caused to flow past and around the permanently magnetized body 480 retained in the bore 306 of the piston rod 222, whereby, in time, the entire volume of hydraulic fluid is subjected to the influence of such magnetized body 480 which acts to attract to it and remove from the hydraulic fluid any ferromagnetic particles which may be present therein, either by reason of external contamination of the fluid from the exterior or wear of the ferromagnetic elements within the apparatus.

It is to be understood that the foregoing is illustrative only and that the invention is not limited thereby, but includes all modifications thereof, within the scope of the invention.

What is claimed is:

1. In a door check mechanism, apparatus comprising:

a hydraulic check cylinder, a cylinder head on said cylinder and a check piston reciprocable in said check cylinder;

a high speed hydraulic fluid discharge passageway communicating with said cylinder intermediate said piston and said cylinder head;

a low speed hydraulic fluid discharge passageway communicable with said cylinder intermediate said piston and said cylinder head;

and means controlled by the piston for closing the high speed passageway before the piston reaches the end of its stroke toward said cylinder head and simultaneously opening said low speed passageway before the piston reaches the end of its stroke toward said cylinder head,

whereby, during the initial portion of the movement of said piston, the hydraulic fluid is discharged through said high speed discharge passageway while said low speed discharge passageway is closed, and whereby, during the final portion of said stroke of said piston, the hydraulic fluid is discharged through said low speed discharge passageway while said high speed passageway is closed.

2. Apparatus in accordance with claim 1, and separate adjustable means for variably controlling the resistance to flow of hydraulic fiuid through at least one such passageway.

3. Apparatus in accordance with claim 1, and separate adjustable means for variably controlling the resistance to flow of hydraulic fiuid through each such passageway.

4. Apparatus in accordance with claim 1, wherein said means controlled by said piston comprises a valve body slidably carried by said piston head and movable by said piston, upon abutment therewith, between a first position in which said high speed passageway is opened and said low speed passageway is closed and a second position in which said high speed passageway is closed and said low speed passageway is opened.

5. Apparatus in accordance with claim 4, in which said high speed passageway comprises a duct in said valve body adapted to be closed by said piston upon abutment thereby by said piston.

6. Apparatus in accordance with claim 4, and separate adjustable means for variably controlling the resistance to flow of hydraulic fluid through each such passageway.

7. In a door check mechanism, apparatus comprising:

a spindle on which a door is adapted to be pivotally mounted;

an actuating cam having an actuating cam surface carried by said spindle;

an actuating spring means;

a cam follower coupled to said spring means and engaging said actuating cam surface under the force of said spring means, the portion of said cam surface engaged by and moving said cam follower being characterized by;

anabruptly radially expanding first portion moving the cam follower such as initially to increase the tension in said spring means at a relatively rapid initial rate as the cam is moved by said spindle from a position corresponding to a fully closed door position to a position corresponding to a slightly opened door position, thereby providing an initial relatively high rotational force to said spindle, resisting the initial opening and tending to return such door to its closed position,

an intermediate, radially expanding cam portion extending from said first portion to a position corresponding to a nearly completely opened door posi tion and moving said cam follower such as to further increase the tension in said spring means at a reduced rate relative to said initial rate and thereby provide a reduced rotational force to said spindle, resisting continued opening and tending to return such door to its closed position,

and a final, radially receding cam portion extending from said intermediate'cam portion and moving said cam follower such as to decrease the tension in said spring means, thereby providing a final rotational force to said spindle tending to continue to open such door to a position corresponding to a fully opened door position and initially resist movement thereof from such fully opened position in a door closing direction.

8. Apparatus in accordance with claim 7, and auxiliary detent latch means separate from the cam structure for adjusting the biasing force by which the door is retained in its fully opened position.

9. In a door pivot mechanism, including an adjustable door supporting means rotatably carried by said mechanism, said means comprising:

a first supporting member having a non-circular, axially extending, first coupling section, and being formed adjacent the inner end of said first coupling section with a coaxial, threaded section;

an adjustment nut axially adjustably carried on said threaded section;

a tapered coupling member having one surface portion thereof axially slidably but non-rotatably couplingly engaging a surface of said non-circular first coupling section, said coupling member also being formed with a non-circular, axially sloping surface opposite said one surface, said coupling member being axially positioned with one axially directed end thereof against said adjustment nut;

and a second supporting member having a non-circular, axially extending, second coupling section having :a sloping surface which corresponds to .and is adapted to make axially detachable, wedging, non-rotatable coupling engagement with said axially sloping surface of said coupling member;

whereby the weight of said door may be normally supported between said first and second supporting members through said sloping surfaces and through said coupling member, which, in turn, engages said adjustrnent nut, whereby said coupling member is adapted to be wedgingly forced diametrically into clamping engagement between said first and second coupling sections, with the axial separation of said first and second coupling members being determined by the axial position of said adjustment nut on said threaded section.

10. In a door pivot mechanism, including an adjustable door supporting means rotatably carried by said mechanism, said means comprising:

a spindle, said spindle being formed at one end thereof with a non-circular, axially extending, coupling section, and being formed adjacent the inner end of said coupling section with a coaxial, threaded section;

an adjustment nut axially adjustably threaded on said threaded section;

a tapered coupling member having an internal surface portion axially slidably but non-rotatably couplingly engaging a surface of said non-circular coupling section, said coupling member also being formed with a non-circular, axially sloping external surface, said coupling member being axially adjustably positioned with one axially directed end thereof supported against said adjustment nut;

and a supporting member having formed therein an internal, non-circular socket having a sloping surface which corresponds to and is adapted to make axially detachable, wedging, non-rotatable coupling engagement with said axially sloping external surface of said coupling member;

whereby the weight of said door may be normally sup ported between said spindle and supporting member through said surfaces, against saidcoupling member, which, in turn, supportingly engages said adjustment nut, whereby said coupling member is adapted to be wedgingly forced diametrically into clamping engagement with said coupling section by the weight of the door, as aforesaid, at any axial position of said coupling member relative to said coupling section as determined by the axial position of said adjustment nut on said threaded section.

11. In a door pivot mechanism, including an adjustable door supporting means rotatably carried by said mechanism, said means comprising:

a spindle, said spindle being formed at one end thereof with a non-circular, non-tapered, axially extending, coupling section, and being formed adjacent the inner end of said coupling section with a coaxial, externally threaded section;

an adjustment nut axially adjustably threaded on said threaded section;

a split coupling sleeve having a non-tapered, non-circular, internal bore portion surrounding and axially slidably but non-rotatably couplingly engaging said coupling section, said coupling sleeve also being formed with a coaxial, non-circular, axially tapered external surface, said coupling sleeve being axially adjustably positioned with one end thereof against said adjustment nut;

and a supporting member having formed therein an internal coaxial non-circular, axially tapered socket, the taper of which corresponds to and is adapted to make axially detachable, wedging, non-rotatable coupling engagement with said tapered external surface of said coupling sleeve,

the weight of said door being normally supported through said tapered surfaces, against said coupling sleeve which, in turn, engages said adjustment nut, whereby said coupling sleeve is adapted to be wedgingly forced diametrically into clamping engagement with said coupling section as aforesaid at any axial position of said coupling sleeve relative to said coupling section as determined by the axial position of said adjustment nut on said threaded section.

12. In a door pivot mechanism, including a door supporting means rotatably carried by said mechanism, said means comprising:

a door spindle, said spindle being formed at the upper end thereof with an external, non-circular, nontapered, axially extending, coupling section, and being formed adjacent the lower end of said coupling section with a coaxial, externally threaded section;

an adjustment nut axially adjustably threaded on said threaded section;

a coupling sleeve having a non-tapered, non-circular,

internal bore portion surrounding land axially slidably but non-rotatably couplingly engaging said coupling section, and formed with a coaxial, non-circular, axially upwardly tapered, external surface, said coupling sleeve being longitudinally split into at least two laterally, oppositely confronting members adapted to radially, clampingly engage said coupling section, said coupling sleeve being axially adjustably supported at its lower end on said adjustment nut;

and a door-supporting member having formed therein an internal, downwardly facing, non-circular, axially upwardly tapered socket, the taper of which corresponds to and is adapted to make axially detachable wedging, non-rotatable coupling engagement with said tapered external surface of said coupling sleeve;

said door-supporting member being normally supported through said tapered surfaces upon said coupling sleeve which is in turn supported on said adjusting nut, whereby said confronting members of said coupling sleeve are adapted to be forced radially inwardly into clamping engagement with said coupling section at any vertical position of said coupling sleeve and door supporting member as determined by the vertical position of said adjustment nut on said threaded section.

13. Apparatus in accordance with claim 12 in which:

said external non-tapered, non-circular external surface of said coupling section comprises a pair of diametrically opposite, axially extending, parallel flat surfaces;

said non-tapered, non-circular internal bore portion of said coupling sleeve comprises a pair of diametrically opposite, axially extending flat surfaces, conforming to and axially slidable on said fiat surfaces of said coupling section;

said non-circular, axially upwardly tapered external surface of said coupling sleeve comprises a pair of diametrically opposite, axially upwardly converging, flat surfaces;

and said downwardly facing, non-circular, axially upwardly tapered socket of said door supporting member comprises a pair of diametrically opposite axially upwardly converging, fiat surfaces conforming to said flat surfaces of said external surface of said coupling sleeve.

14. In a door check mechanism, apparatus comprising:

a hydraulic check cylinder having a cylinder head end and an axially opposite piston rod end;

a piston axially reciprocable in said check cylinder in response to swinging movements of a door connected to said mechanism;

a hydraulic fluid duct through said piston interconnecting said cylinder head end and said piston rod end on axially opposite sides of said piston;

a one-way check valve means in said fluid duct normally operative to permit fluid flow through said duct in said piston from said piston rod end to said cylinder head end when said piston is moved axially in said cylinder away from said cylinder head end toward said piston rod end, and to prevent fluid flow through said duct in said piston from said cylinder head end to said piston rod end when said piston is moved axially in said cylinder away from said piston rod end toward said cylinder head end;

and fluid pressure relief means included in said check valve means operative in response to a predetermined excessive fluid pressure in said cylinder head end relative to that in said piston rod end of said cylinder, for opening a fluid bypass channel around said check valve means, to permit flow of fluid through said duct in said piston from said head end to said piston rod end of said cylinder, said check valve means and fluid pressure relief means including:

a relief valve bore coaxially contained within said piston and forming a portion of said fluid duct through said piston;

a tubular relief valve body axially slidable in said relief valve bore, said valve body being of such form as to provide a fluid flow passage from end-to-end thereof through clearance space provided between said tubular relief valve body and the said relief valve bore, and said relief valve body also having a fluid passage extending axially therethrough from end-to-end thereof, the end of said relief body most adjacent the head end of said piston having a first annular valve seat surrounding the adjacent entrance to said fluid passage;

a second annular valve seat formed in said relief valve bore adjacent the head end thereof, said first and second valve seats being coaxial, and said first valve seat being adapted sealingly to engage said second valve seat to close said fluid passage formed through said clearance space;

and resilient means within said relief valve bore biasing said relief valve body axially in said relief valve bore such as normally to maintain said first valve seat in such sealing engagement with said second valve seat.

15. Apparatus in accordance with claim 14 in which said resilient means comprises a spring coaxially contamed in said relief valve bore;

and a permanently magnetized body contained within said spring.

16. Apparatus in accordance with claim 14 in which:

said one-way check valve is located on the end of said relief valve body and serves to control fluid flow through the said fluid flow passage therethrough.

17. In a door check mechanism, a hydraulic cushion check means comprising:

a cylinder having a cylinder bore means therein;

a piston means coaxially reciprocable into and out of said cylinder bore means in response to swinging movement of a door connected thereto,

at least one of said means being axially tapered for at least a portion of its axial length, whereby, as said piston means initially enters said bore means, a progressively decreasing annular clearance space is formed between the adjacent surfaces of said means for escape of hydraulic fluid entrapped within said cylinder bore means by said entering piston means;

container means for maintaining said cylinder bore means and said piston means submerged in a body of hydraulic fluid;

a fluid bypass passage interconnecting axially opposite ends of said piston means for flow of hydraulic fiuid therethrough from one end to the other of said piston means as induced by reciprocation of said piston means into and out of said cylinder bore, as aforesaid;

and fluid flow resistance means in said fluid bypass passage, said fluid flow resistance means including means for varying its fluid flow resistance characteristics in accordance with a predetermined function means restraining rotation of said adjustment nut but permitting axial movement thereof relative to said cylinder block portion;

and a helical power spring coaxially surrounding said check plunger and extending, under compression, between said adjustment nut means and said check piston,

whereby a bias is applied to said check piston and check plunger tending to move them in a direction towards said check cylinder;

and whereby rotation of said plunger guide in said cylindrical bore in said partition, results in rotation of said externally threaded clyindrical member relative to said adjustment nut, thereby adjustably varying the axial position of said adjustment nut relative to said partition and thereby varying the axially compressed length of said power spring to vary the aforesaid bias.

20. Apparatus according to claim 19, and a spindle housing and reciprocable therewith in following relation to said cam means, whereby axial movement of said plunger and rotational movement of said cam means and spindle are restrained to a predetermined variable relationship to one another;

whereby said carn follower means is biased in a direction toward said check cylinder and is pressed thereby into actuating engagement with said cam means.

21. In a door check and suspension assembly, apparatus of its temperature, whereby the resistance to flow comprising:

of said hydraulic fluid through said bypass passage a mechanism case having a cam housing portion adis thereby maintained approximately constant with jacent one end thereof and a hollow cylinder block changes of temperature thereof. portion adjacent the opposite end thereof, there being 18. Apparatus according to claim 17, wherein said a check cylinder bore formed in said cylinder block fluid flow resistance means includes: 1 portion parallel with the longitudinal axis of said an aperture and control means to vary the size of said case;

aperture; a transversely extending support within said mechanism and a thermostatic element coupled to said control case between said cam housing portion and said and means and operative to reduce or increase the cylinder block portion, said partition having formed size of said aperture as the temperature of said elethrough it a cylindrical bore having its axis parallel ment respectively increases or decreases. with said longitudinal axis;

19. In a door check and suspension assembly, apa plunger guide rotatably and axially supported in said paratus comprising: cylindrical bore, said plunger guide having formed an elongated, mechanism case formed with a hollow, integrally therewith an externally threaded, cylindriinitially open-topped, cam housing portion adjacent cal member projecting into said cylinder block one end thereof and a cylinder block portion adportion and having a coaxial plunger guide bore;

jacent the opposite end thereof, there being a check a check piston axially reciprocable in said check cylcylinder bore formed in said cylinder block portion inder;

parallel with the longitudinal axis of said case; a plunger attached to said piston and extending axially a detachable cover plate for closingly covering the top slidable through said plunger guide bore into said of said cam housing portion; cam housing;

a transversely extending partition fixed within said an internally threaded adjustment nut means threadedly mechanism case separating said cam housing portion carried on said externally threaded cylindrical memfrom said cylinder block portion, said partition havber, said adjustment nut and said cylinder block ing formed through it a cylindrical bore having an 3 portion including means for restraining rotation of axis parallel with said longitudinal axis; said adjustment nut but permitting axial movement and a plunger guide supported in said cylindrical bore thereof relative to said cylinder block portion;

and having a coaxial plunger guide bore thereand a helical power spring coaxially surrounding said through, said plunger guide includes an externally check plunger and extending, under compression, belthreaded, cylindrical member projecting into said cy- 0 tween said adjustment nut means and means conlindrical member protecting into said cylinder block nected to said check piston, portion; whereby said check piston and check plunger are and a check piston axially reciprocable in said check biased in a direction toward said check cylinder, and

cylinder; whereby rotation of said plunger guide in said cya plunger attached to said piston and extending axially lindrical bore in said support results in rotation of slidable through said plunger guide bore into said said externally threaded cylindrical member relative cam housing; to said adjustment nut, thereby adjustably varying the an internally threaded adustment nut means threadedly axial position of said adjustment nut means on said carried on said externally threaded cylindrical cylindrical member and accordingly varying the axialmember; ly compressed length of said power spring to vary the aforesaid bias.

22. Apparatus according to claim 19, in which said means restraining rotation of said adjustment nut but permitting axial movement thereof includes a key member extending generally radially from said adjustment nut into longitudinal sliding engagement with an inwardly facing, longitudinally extending slot formed in the interior of said cylinder block portion.

23. In a door check and suspension assembly, apparatus comprising:

an elongated, one-piece mechanism case formed with a hollow cam housing portion adjacent one end thereof and a hollow cylinder block portion adjacent the opposite end thereof, there being a check cylinder bore formed in said cylinder block portion parallel with the longitudinal axis of said case;

an integrally formed, transversely extending partition within said mechanism case, separating said cam housing portion from said cylinder block portion, said partition having formed through it a cylindrical bore having an axis parallel with said longitudinal axis; a plunger guide rotatably supported in said cylindrical bore, said plunger guide having formed integrally therewith an externally threaded, cylindrical member shaft rotatably supported in bearings carried in said cam housing for rotation about an axis generally perpendicular to said longitudinal axis;

and cam means in said cam housing fixed to said spindle and rotatable therewith; cam follower means carried by said plunger in said cam projecting into said cylinder block portion and having a coaxial plunger guide bore;

and a spindle shaft rotatably supported in bearings carried in said cam housing and said cover plate for rotation about an axis generally perpendicular to said longitudinal axis;

a check piston axially reciprocable in said check cylinder;

a plunger attached to said piston and extending axially slidable through said plunger guide bore into said cam housing;

cam means in said cam housing fixed to said spindle and rotatable therewith and cam follower means carried by said plunger in said cam housing and reciprocable therewith in following relation to said cam means; whereby axial movement of said plunger and rotational movement of said cam means and spindle are restrained to a predetermined variable relationship to one another;

an internally threaded adjustment nut means threadedly carried on said externally threaded cylindrical memher, said adjustment nut and said cylinder block portion including means restraining rotation of said adjustment -nut but permitting axial movement thereof relative to said cylinder block portion;

and a helical power spring coaxially surrounding said check plunger and extending, under compression, between said adjustment nut means and said check piston,

whereby said check piston, check plunger and cam follower are biased in a direction toward said check cylinder and said cam follower means is pressed thereby into actuating engagement with said cam means,

and whereby rotation of said plunger guide in said cylindrical bore in said partition results in rotation of said externally threaded cylindrical member relative to said adjustment nut, thereby adjustably varying the axially compressed length of said power spring to vary the aforesaid bias.

References Cited UNITED STATES PATENTS Lonbom et a1. 16-49 Hubbs et al. 16-55 Bommer 16-52 XR Carlson 16-55 Carlson 16-55 Carlson 16-55 West 16-151 XR Sasse 16-51 Voester et a1. 16-55 Millard et a1 16-52 Sanchez 16-49 Brooks 335-305 Webb et al 16-62 Armento 16-55 FOREIGN PATENTS US. Cl. X.R.

233g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, Dated June 17,

lnvefitofls) F. J. RUSSELL and GEORGE B. SOLOVIEFF It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 23, line 40, cancel "said cy line 41, cancel "indrical member protecting into" 5mm km SEMI mva m Attest:

Edmdllkubmlrmuuz. mum, JR- (bl-hum at Putin 

